问题
                    
My secretary told me just now that she ________ typing the letters by the time I went back, which I do have some doubt about. You know, she is not that efficient a girl.
                            A:would finish
B:had finished
C:would have finished
D:will finish
                        
                        B:had finished
C:would have finished
D:will finish
正确答案是:
                        